Archana Singh-Manoux

Association of Socioeconomic Position With Health Behaviors and Mortality

CONTEXT Previous studies may have underestimated the contribution of health behaviors to social inequalities in mortality because health behaviors were assessed only at the baseline of the study. OBJECTIVE To examine the role of health behaviors in the association between socioeconomic position and mortality and compare whether their contribution differs when assessed at only 1 point in time with that assessed longitudinally through the follow-up period. DESIGN, SETTING, AND PARTICIPANTS Established in 1985, the British Whitehall II longitudinal cohort study includes 10 308 civil servants, aged 35 to 55 years, living in London, England. Analyses are based on 9590 men and women followed up for mortality until April 30, 2009. Socioeconomic position was derived from civil service employment grade (high, intermediate, and low) at baseline. Smoking, alcohol consumption, diet, and physical activity were assessed 4 times during the follow-up period. MAIN OUTCOME MEASURES All-cause and cause-specific mortality. RESULTS A total of 654 participants died during the follow-up period. In the analyses adjusted for sex and year of birth, those with the lowest socioeconomic position had 1.60 times higher risk of death from all causes than those with the highest socioeconomic position (a rate difference of 1.94/1000 person-years). This association was attenuated by 42% (95% confidence interval [CI], 21%-94%) when health behaviors assessed at baseline were entered into the model and by 72% (95% CI, 42%-154%) when they were entered as time-dependent covariates. The corresponding attenuations were 29% (95% CI, 11%-54%) and 45% (95% CI, 24%-79%) for cardiovascular mortality and 61% (95% CI, 16%-425%) and 94% (95% CI, 35%-595%) for noncancer and noncardiovascular mortality. The difference between the baseline only and repeated assessments of health behaviors was mostly due to an increased explanatory power of diet (from 7% to 17% for all-cause mortality, respectively), physical activity (from 5% to 21% for all-cause mortality), and alcohol consumption (from 3% to 12% for all-cause mortality). The role of smoking, the strongest mediator in these analyses, did not change when using baseline or repeat assessments (from 32% to 35% for all-cause mortality). CONCLUSION In a civil service population in London, England, there was an association between socioeconomic position and mortality that was substantially accounted for by adjustment for health behaviors, particularly when the behaviors were assessed repeatedly.

Subjective social status: its determinants and its association with measures of ill-health in the Whitehall II study.

The purpose of this study was twofold-(1) investigate the role of subjective social status as a predictor of ill-health, with a further exploration of the extent to which this relationship could be accounted for by conventional measures of socioeconomic position; (2) examine the determinants of a relatively new measure of subjective social status used in this study. A 10 rung self-anchoring scale was used to measure subjective social status in the Whitehall II study, a prospective cohort study of London-based civil service employees. Results indicate that subjective status is a strong predictor of ill-health, and that education, occupation and income do not explain this relationship fully for all the health measures examined. The results provide further support for the multidimensional nature of both social inequality and health. Multiple regression shows subjective status to be determined by occupational position, education, household income, satisfaction with standard of living, and feeling of financial security regarding the future. The results suggest that subjective social status reflects the cognitive averaging of standard markers of socioeconomic situation and is free of psychological biases.

Job strain as a risk factor for coronary heart disease: A collaborative meta-analysis of individual participant data

Summary Background Published work assessing psychosocial stress (job strain) as a risk factor for coronary heart disease is inconsistent and subject to publication bias and reverse causation bias. We analysed the relation between job strain and coronary heart disease with a meta-analysis of published and unpublished studies. Methods We used individual records from 13 European cohort studies (1985–2006) of men and women without coronary heart disease who were employed at time of baseline assessment. We measured job strain with questions from validated job-content and demand-control questionnaires. We extracted data in two stages such that acquisition and harmonisation of job strain measure and covariables occurred before linkage to records for coronary heart disease. We defined incident coronary heart disease as the first non-fatal myocardial infarction or coronary death. Findings 30 214 (15%) of 197 473 participants reported job strain. In 1·49 million person-years at risk (mean follow-up 7·5 years [SD 1·7]), we recorded 2358 events of incident coronary heart disease. After adjustment for sex and age, the hazard ratio for job strain versus no job strain was 1·23 (95% CI 1·10–1·37). This effect estimate was higher in published (1·43, 1·15–1·77) than unpublished (1·16, 1·02–1·32) studies. Hazard ratios were likewise raised in analyses addressing reverse causality by exclusion of events of coronary heart disease that occurred in the first 3 years (1·31, 1·15–1·48) and 5 years (1·30, 1·13–1·50) of follow-up. We noted an association between job strain and coronary heart disease for sex, age groups, socioeconomic strata, and region, and after adjustments for socioeconomic status, and lifestyle and conventional risk factors. The population attributable risk for job strain was 3·4%. Interpretation Our findings suggest that prevention of workplace stress might decrease disease incidence; however, this strategy would have a much smaller effect than would tackling of standard risk factors, such as smoking. Funding Finnish Work Environment Fund, the Academy of Finland, the Swedish Research Council for Working Life and Social Research, the German Social Accident Insurance, the Danish National Research Centre for the Working Environment, the BUPA Foundation, the Ministry of Social Affairs and Employment, the Medical Research Council, the Wellcome Trust, and the US National Institutes of Health.

Does Subjective Social Status Predict Health and Change in Health Status Better Than Objective Status

Objective: To examine, among middle-aged individuals, if subjective socioeconomic status (SES) predicts health status and change in health status over time better than objective SES. Methods: Data are from the Whitehall II study, a prospective study of British civil servants. SES data are drawn from Phase 5 (1997–1999) of the study and health data from Phases 5 and 6 (2000–2001). Physical and mental component scores from the Short Form 36, the General Health Questionnaire, and self-rated health were used to assess health status. Multiple linear regressions were used to examine the relationship between SES and health and change in health status. Results: Complete data were available on 5486 people. Results show both measures of SES to be global measures of SES. Both measures of SES were significantly associated with health outcomes and with decline in health status over time. However, when both objective and subjective measures of SES are entered simultaneously in the model to predict change in health status, it was only the latter that continues to be significantly associated with health and changes in health. Conclusions: Subjective SES is a better predictor of health status and decline in health status over time in middle-aged adults. These results are discussed in terms of three possible explanations: subjective SES is a more precise measure of social position, the results provide support for the hierarchy-health hypothesis, and the results could be an artifact of common method variance. SES = socioeconomic status; SF 36 = Short Form 36; PCS = physical component score; MCS = mental component score; GHQ = General Health Questionnaire.

Timing of onset of cognitive decline: results from Whitehall II prospective cohort study.

Objectives To estimate 10 year decline in cognitive function from longitudinal data in a middle aged cohort and to examine whether age cohorts can be compared with cross sectional data to infer the effect of age on cognitive decline. Design Prospective cohort study. At study inception in 1985-8, there were 10 308 participants, representing a recruitment rate of 73%. Setting Civil service departments in London, United Kingdom. Participants 5198 men and 2192 women, aged 45-70 at the beginning of cognitive testing in 1997-9. Main outcome measure Tests of memory, reasoning, vocabulary, and phonemic and semantic fluency, assessed three times over 10 years. Results All cognitive scores, except vocabulary, declined in all five age categories (age 45-49, 50-54, 55-59, 60-64, and 65-70 at baseline), with evidence of faster decline in older people. In men, the 10 year decline, shown as change/range of test×100, in reasoning was −3.6% (95% confidence interval −4.1% to −3.0%) in those aged 45-49 at baseline and −9.6% (−10.6% to −8.6%) in those aged 65-70. In women, the corresponding decline was −3.6% (−4.6% to −2.7%) and −7.4% (−9.1% to −5.7%). Comparisons of longitudinal and cross sectional effects of age suggest that the latter overestimate decline in women because of cohort differences in education. For example, in women aged 45-49 the longitudinal analysis showed reasoning to have declined by −3.6% (−4.5% to −2.8%) but the cross sectional effects suggested a decline of −11.4% (−14.0% to −8.9%). Conclusions Cognitive decline is already evident in middle age (age 45-49).

What does self rated health measure? Results from the British Whitehall II and French Gazel cohort studies

Objectives: To investigate the determinants of self rated health (SRH) in men and women in the British Whitehall II study and the French Gazel cohort study. Methods: The cross sectional analyses reported in this paper use data from wave 1 of the Whitehall II study (1985–88) and wave 2 of the Gazel study (1990). Determinants were either self reported or obtained through medical screening and employer’s records. The Whitehall II study is based on 20 civil service departments located in London. The Gazel study is based on employees of France’s national gas and electricity company (EDF-GDF). SRH data were available on 6889 men and 3403 women in Whitehall II and 13 008 men and 4688 women in Gazel. Results: Correlation analysis was used to identify determinants of SRH from 35 measures in Whitehall II and 33 in Gazel. Stepwise multiple regressions identified five determinants (symptom score, sickness absence, longstanding illness, minor psychiatric morbidity, number of recurring health problems) in Whitehall II, explaining 34.7% of the variance in SRH. In Gazel, four measures (physical tiredness, number of health problems in the past year, physical mobility, number of prescription drugs used) explained 41.4% of the variance in SRH. Conclusion: Measures of mental and physical health status contribute most to the SRH construct. The part played by age, early life factors, family history, sociodemographic variables, psychosocial factors, and health behaviours in these two occupational cohorts is modest.

When reciprocity fails: effort–reward imbalance in relation to coronary heart disease and health functioning within the Whitehall II study

Background: A deleterious psychosocial work environment, as defined by high efforts expended in relation to few rewards reaped, is hypothesised to increase the risk of future poor health outcomes. Aims: To test this hypothesis within a cohort of London based civil servants. Methods: Effort–reward imbalance (ERI) was measured among 6895 male and 3413 female civil servants aged 35–55 during the first phase of the Whitehall II study (1985–88). Participants were followed until the end of phase 5 (1997–2000), with a mean length of follow up of 11 years. Baseline ERI was used to predict incident validated coronary heart disease (CHD) events during follow up and poor mental and physical functioning at phase 5. Results: A high ratio of efforts in relation to rewards was related to an increased incidence of all CHD (hazard ratio (HR) = 1.36, 95% CI 1.12 to 1.65) and fatal CHD/non-fatal myocardial infarction (HR = 1.28, 95% CI 0.89 to 1.84) during follow up, as well as poor physical (odds ratio (OR) = 1.47, 95% CI 1.24 to 1.74) and mental (OR = 2.24, 95% CI 1.89 to 2.65) functioning at phase 5, net of employment grade. A one item measure of high intrinsic effort also significantly increased the risk of these health outcomes, net of grade. ERI may be particularly deleterious with respect to CHD risk among those with low social support at work or in the lowest employment grades. Discussion: Within the Whitehall II study, a ratio of high efforts to rewards predicted higher risk of CHD and poor physical and mental health functioning during follow up. Although the increased risk associated with ERI was relatively small, as ERI is common it could be of considerable public health importance.

Health Behaviours, Socioeconomic Status, and Mortality: Further Analyses of the British Whitehall II and the French GAZEL Prospective Cohorts

Further analysis of data from two prospective cohorts reveals differences in the extent to which health behaviors attenuate associations between socioeconomic position and mortality outcomes.

Self-rated health before and after retirement in France (GAZEL): a cohort study

BACKGROUND Governments need to increase the proportion of the population in work in most developed countries because of ageing populations. We investigated longitudinally how self-perceived health is affected by work and retirement in older workers. METHODS We examined trajectories of self-rated health in 14 714 employees (11 581 [79%] men) from the French national gas and electricity company, the GAZEL cohort, for up to 7 years before and 7 years after retirement, with yearly measurements from 1989 to 2007. We analysed data by use of repeated-measures logistic regression with generalised estimating equations. FINDINGS Overall, suboptimum health increased with age. However, between the year before retirement and the year after, the estimated prevalence of suboptimum health fell from 19.2% (95% CI 18.5-19.9) to 14.3% (13.7-14.9), corresponding to a gain in health of 8-10 years. We noted this retirement-related improvement in men (odds ratio 0.68, 95% CI 0.64-0.73) and women (0.74, 0.67-0.83), and across occupational grades (low 0.72, 0.63-0.82; high 0.70, 0.63-0.77), and it was maintained throughout the 7 years after retirement. A poor work environment and health complaints before retirement were associated with a steeper yearly increase in the prevalence of suboptimum health while still in work, and a greater retirement-related improvement; however, people with a combination of high occupational grade, low demands, and high satisfaction at work showed no such retirement-related improvement. INTERPRETATION These findings suggest that the burden of ill-health, in terms of perceived health problems, is substantially relieved by retirement for all groups of workers apart from those with ideal working conditions, and that working life for older workers needs to be redesigned to achieve higher labour-market participation. FUNDING Swedish Council for Working Life and Social Research, Academy of Finland, INSERM (France), BUPA Foundation (UK), European Science Foundation, and Economic and Social Research Council (UK).

Measures of frailty in population-based studies: an overview

BackgroundAlthough research productivity in the field of frailty has risen exponentially in recent years, there remains a lack of consensus regarding the measurement of this syndrome. This overview offers three services: first, we provide a comprehensive catalogue of current frailty measures; second, we evaluate their reliability and validity; third, we report on their popularity of use.MethodsIn order to identify relevant publications, we searched MEDLINE (from its inception in 1948 to May 2011); scrutinized the reference sections of the retrieved articles; and consulted our own files. An indicator of the frequency of use of each frailty instrument was based on the number of times it had been utilized by investigators other than the originators.ResultsOf the initially retrieved 2,166 papers, 27 original articles described separate frailty scales. The number (range: 1 to 38) and type of items (range of domains: physical functioning, disability, disease, sensory impairment, cognition, nutrition, mood, and social support) included in the frailty instruments varied widely. Reliability and validity had been examined in only 26% (7/27) of the instruments. The predictive validity of these scales for mortality varied: for instance, hazard ratios/odds ratios (95% confidence interval) for mortality risk for frail relative to non-frail people ranged from 1.21 (0.78; 1.87) to 6.03 (3.00; 12.08) for the Phenotype of Frailty and 1.57 (1.41; 1.74) to 10.53 (7.06; 15.70) for the Frailty Index. Among the 150 papers which we found to have used at least one of the 27 frailty instruments, 69% (n = 104) reported on the Phenotype of Frailty, 12% (n = 18) on the Frailty Index, and 19% (n = 28) on one of the remaining 25 instruments.ConclusionsAlthough there are numerous frailty scales currently in use, reliability and validity have rarely been examined. The most evaluated and frequently used measure is the Phenotype of Frailty.